Feeder and stacker

ABSTRACT

A machine for automatically feeding and coupling individual sheets of material to an adjacent run of an overdisposed highspeed belt conveyor by which the sheets are transferred to one or more remote locations and from which the same are selectively released, discharged and stacked in preselected groups; the feeding, coupling and the selective discharge functions being automatically carried out by selective control of the ambient atmosphere about the conveyor and sheet materials.

United States Patent [72] Inventor Loren B. Barker Salem, Ill. [21] Appl. No. 778,252 [22] Filed Nov. 22, 1968 [45] Patented -Oct. 19, 1971 [73] As'sig'nee Lear Siegler, Inc.

Salem, Ill.

[54] FEED ER AND STACKER 9 Claims, 11 Drawing Figs.

[52] US. Cl 209/125, 209/74, 271/74 [51] Int. Cl B07c 3/06 [50] Field of Search 209/74, 125; 271/4, 34, 74

[5 6] References Cited UNITED STATES PATENTS 3,126,200 3/1964 Rehm 271/34 X 3,227,275 1/1966 Cody 271/74 X 3,395,915 8/1968 Clausen.. 271/74 3,476,241 11/1969 Ungerer 271/74 X Primary Examiner-Richard A. Schacher Attorney-Davis, Lucas, Brewer & Brugman stacked in preselected groups; the feeding, coupling and the selective discharge functions being automatically carried out by selective control of the ambient atmosphere about the conveyor and sheet materials.

Run 7 sum:

PATENTEDBCI 19 1911 SHEET 10F 5 J a lawman! PATENTEDucT 19 I9?! I 3,613,886

' sum 3 OF 5 FEEDER AND STACKER This invention relates generally to the material-handling art and particularly to improvements in apparatus for performing the functions of separating, feeding, conveying, sorting and stacking sheet materials.

Briefly, apparatus according to the concepts of this inven tion comprises high-speed endless conveyor means, particularly impervious belt or web conveyors, movable adjacently over sheet materials to be handled. A subatmospheric plenum or chamber is associated with the endless conveyor means in a manner to control selectively spaced zones of the atmosphere thereabout. Opposing surfaces of sheet materials positioned adjacent the conveyor are consequently subjected to selectively controlled differentials of ambient atmospheres adjacent such controlled zones, whereby to cause the materials to move onto, off of, and with the conveyor without interrupting high-speed movement of the latter.

An important object of this invention is to provide improved material-handling means for high-speed transfer of sheet materials.

Another object of this invention is to provide improved means, aforesaid, which combines endless conveyor means for transferring sheet materials between spaced locations with means for differentially controlling pressure and flow of the atmosphere on opposing surfaces of sheet materials thereby to effectuate desired movements of such materials relative to and with the conveyor means.

An additional object of this invention is to provide improved means for separating, feeding, sorting, stacking and transporting sheet materials.

Still another object of this invention is to provide high-speed conveyor means for handling sheet materials which is capable of separating sheet materials from a stack, one by one, depositing and holding such sheets on a moving conveyor and automatically discharging such sheets therefrom at selected locations by selectively controlled atmospheric forces.

A still further object of this invention is to provide apparatus for the high-speed handling of sheet materials which is economical to manufacture and which is efficient and dependably in operation.

Having thus described this invention the above and further objects, features and advantages thereof will be recognized by those familiar with the art from the following detailed description of a preferred embodiment of its features and concepts, illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a schematic diagram illustrating a typical operational installation utilizing apparatus according to this invention;

FIG. 2 is a view in side elevation of apparatus embodying the features of this invention;

FIG. 3 is a top plan view thereof;

FIG. 4 is an end elevational view thereof;

FIG. 5 is an enlarged partial cross-sectional view taken substantially along vantage line 5--5 of FIG. 3 and looking in the direction of the arrows thereon;

FIG. 6 is a partial cross-sectional view, with parts shown in elevation, taken substantially along vantage line 66 of FIG. 5 and looking in the direction of the arrows thereon;

FIG. 7 is a partial enlarged view in end elevation, with parts broken away in section, taken substantially along vantage line 7-7 of FIG. 3 to illustrate structural features of the vacuum chamber; and

FIGS. 8-11 are a series of partial side elevational views of the apparatus shown in FIG. 2 and illustrating successive positions of sheet materials moving from a stack to the conveyor means.

Turning now to the details of the particular embodiment of the present invention illustrated in the accompanying drawings, reference is made to FIG. 1 wherein material-handling apparatus 10 is schematically represented in tandem operating alignment with infeeding, inspection conveyor means II. This type of installation permits use of the present invention for purpose of grading, sorting and stacking sheet materials, such as ceiling tile, plywood, particle board laminated board, cardboard, glass and sheet metal stock, such as aluminum or lightweight steel. It is to be recognized, however, that this invention is by no means restricted to such specific use or to the handling of such listed materials inasmuch as the principles and concepts hereof apply with equal facility to a multiplicity of sheet items, from paper to floor tile varying in density and weight and to uses other than stacking, such as a conveyor or feeder to other conveyors, etc. as will be readily recognized and suggested to those familiar with this art from the description of this invention which appears hereinafter.

Be that as it may, in the installation shown in FIG. I, the inspection conveyor means 11 feeds single sheets 12 to apparatus 10 at feed speeds regulated to permit visual inspection of each sheet as it advances to the receiving end of the apparatus 10. In this particular illustrative instance apparatus 10 operates to sort and stack the sheets, depositing the same at selected prime and reject stations 13 and 14, respectively. Selective control of the deposit station for stacking each sheet passing through apparatus 10, is carried out by a human agent or inspector who manually controls a reject controller 15. In a normal sequence, a prime or acceptable sheet of material automatically is deposited at the prime stack station 13 without operation of reject controller 15. In the event a defective sheet or materials is detected by the inspector, operation of the reject controller 15 automatically effects the deposit of that sheet at the reject station 14 (see FIG. 2).

The general structure aspects of the illustrated apparatus 10 embodying this invention, are readily discernible from FIGS. 2-4 of the drawings. As seen therein, apparatus 10 includes a supporting metal frame, indicated generally by numeral 20 in FIG. 2 comprising four upright, ground-engaging legs 21, 21, each fitted with a base pad 22, at its lower end, adapted to be anchored to an undersupport, such as a concrete floor, by bolts 23 or the like. The several legs 21 typically are sections of rectangular tubular steel, which are interjoined at their upper ends by connecting rectangular framework comprising two parallel spaced, elongated side rail members 24, 24 and two parallel spaced end rail members 25, 25. The side and end rail members are related at right angles and securely welded or otherwise fixed to the upper ends of the four corner disposed legs 21, 21 to provide a rigid frame of generally rectangular plan configuration, (see FIG. 3). In its installed position, frame 20 is aligned as shown in FIG. 3 of the drawings, with the side and end rail members 24 and 25 respectively, horizontally parallel to the undersupporting concrete floor.

Suspended from frame 20 and located between its four legs 211, 21, slightly below the level of the side and end rails 24 and 25 thereof, is a hollow, generally rectangular, boxlike assembly 29 (see FIG. 4). The hollow interior of assembly 29 forms a vacuum plenum or chamber 30 while a conveyor means is mounted about the exterior thereof. As best shown in FIGS. 4 and 5, assembly 29 comprises a pair of parallel spaced, elongated sidewall members 31, 31 formed by metal C-channel beams (see FIG. 5) which are cross-connected, intermediate, but near their ends, by transverse C-channel end wall members 32, 32. The bottom side of the assembly 29 is formed by a generally planar sheet metal bottom wall member 33 (see FIG. 3) fixed to bottom flange portions of the side and end wall members. Bottom wall 33 is distinguished by plural rectangular-shaped openings 34, 34; 35, 35 and 36, 36, arranged in spaced sets, coaxially aligned along axes lying normal to the longitudinal axis of the assembly 29 and spaced at intervals along the length of the bottom wall 33 thereof. One set of three openings 34, 34 is located adjacent the left-hand end of the bottom wall 33, as best shown in FIG. 3. A second set of three openings 35, 35 is located generally midway over the reject station 14 while the third set of openings 36, 36, is located near the left-hand margin of the prime stack station 13, in the particular illustrated embodiment of this invention.

While there are three sets of spaced openings in the bottom wall in the illustrated apparatus 10, it is to be understood that additional sets may be employed, depending on the length of the conveyor and the size of the sheet materials to be handled. In essence the spacing between adjacent opening sets along the length of bottom wall 33 is selectively maintained just slightly less than the length of the sheets to be handled. Similarly, the number and size of the openings in each set is determined by such factors as sheet width, density, weight, porosity, flexibility, strength and thickness of material. Lateral spacing between adjacent openings is generally determined by the number of endless conveyor belts employed.

The upper side of the assembly 29 is substantially covered over by a planar top wall member 38 which comprises a generally rectangular sheet metal plate, having plural (herein three) laterally spaced, rectangular-shaped, elongated openings paralleling the longitudinal axis of wall 38 and terminating intermediate, but near the opposite ends thereof. Such three openings are indicated at 39, 40 and 41 in FIG. 3 of the drawings. As best shown in FIG. 7 of the drawings, each such opening is bordered by a respectively associated upstanding collar member 42, 43 and 44 substantially I-shaped cross section. The two outboard collar members 42 and 44 are vertically movable between the full and dotted line positions therefor, indicated in FIG. 7. Contrastingly, the central collar member 43, which borders the central opening 40 in top wall member 38 is rigidly fixed in its raised position, preferably being welded in place. It will be particularly noted that the central collar member 43 carries an outwardly projecting flange portion 45 about its upper end which is bordered along its lateral margins by a pair of elongated laterally projecting coplanar cover plates 46, 46.

Like collar 43, the collar members 42 and 44 are formed with a generally I-shaped cross section, having outwardly extending flange portions 47 and 48 at the upper and lower ends thereof, respectively. The upper flange portions 47 of the collar members 42, 44 partially underlap the cover plates 46, 46 which project laterally outwardly along opposite sides of the centrally disposed fixed collar member 43. Thus, when the two outboard collar members 42, 44 are in their raised or dotted line positions of FIG. 7 an enclosed passageway or space 50 of generally rectangular cross-sectional configuration is formed between the central collar member 43 and each of the two raised outboard collar members 42 and 44 (see FIG. 7). The purpose and functioning of such lengthwise extending channel passageways 50, 50 will be amplified in greater detail hereinafter.

Mounted over the upper wall member 38 of the vacuum plenum and particularly overcovering the longitudinally extending openings 39, 40 and 41 therein, is a sheet metal hood, indicated generally by numeral 55 shown best in FIGS. 2, 3 and 4 of the drawings, Hood 55 includes a pair of parallel spaced sidewall members 56, 56, generally semitrapezoidal in side elevation, which are interjoined by a transversely related and cross-connecting top wall 57 and at one end by end wall 58 as shown in FIG. 2.

Top wall 57 is distinguished by a rectangular trap door 59 mounted to swing about hinge means 60 to provide convenient access to the interior of the hood means 55 as for inspection and repair purposes.

Adjacent the right-hand end wall 58 of the hood 55, as viewed in FIG. 2 in particular, and supported on the framework 20, is a blower means 61 having a discharge outlet 62. Electric motor means 64 drives blower 61 by means of an associated belt and sheave wheel drive means 65. A variablespeed drive unit 66, having manually adjustable control means 67, is coupled to the motor means 64 whereby the speed of the blower means 61 may be infinitely varied in accordance with the operating demands of apparatus 10, as will be amplified in greater particular hereinafter.

Mounted about the enclosed vacuum plenum 30, defined by the space enclosed between the walls 31, 32, 33 and 38 as hereinabove described, are at least two (herein four) generally impervious endless conveyor belts 70, 71, 72 and 73. Such belts extend lengthwise of and operative circulate about the vacuum plenum of assembly 29 in parallel spaced relationship to the plenums longitudinal axis. Belts 71 and 72 are trained along parallel paths intermediate the lateral limits of the vacuum plenum so that the lower runs thereof pass closely adjacent bottom wall 33 between adjacent opposed end of the middle and outboard openings of the several sets of openings 34, 35 and 36. The outboard belts 70 and 73 similarly pass about the plenum adjacent the side margins thereof, with their lower runs immediately adjacent the outer ends or limits of the outboard openings of the spaced sets of openings 34, 35 and 36 (see FIG.5). t

The belts 70-73 are supported at one end of assembly 29 on spaced drive rollers 74, 75, 76 and 77, respectively, located at the right-hand end of apparatus 10 as viewed in FIGS. 2, 3 and 4). Roller 74-77 are mounted on a single common drive shaft 78 extending horizontally between end portions of the C- channel side members 31, 31 of the plenum assembly which extend beyond the end wall member 32 thereof. Bearing means 79 for shaft 78 are carried near the outer ends of members 31, 31. Additional bearing means 80 and 81 are carried by intermediate stub channel support members 82, 83, protruding outwardly of the right hand end wall 32 of the plenum structure. Such stub channels 82 and 83 are disposed in parallel relationship intermediate the side channel wall members 31, 31 as best shown in FIG. 4 of the drawings.

Driving rotation is imparted to shaft 78 by chain or belt drive means 85 actuated by motor means 86 having an associated variably speed drive means 87 equipped with manually adjustably controller means 88. The variable-speed drive 87 and its controller means 88 are similar to that employed in association with the blower motor 64. Therefore the driving speed imparted to shaft 78 may be selectively regulated to variably control the speed of movement or feed speed of the endless belts 70-73, according to operational demands. The motor and drive means are also reversible to provide reverse operation of the conveyor belts desirable for certain operations of apparatus 10, as will appear later herein.

As above described, drive rollers support the belts 70-73 at one end of assembly 29. At the opposite end of assembly 29 the belts are supported by idler rollers 90. As shown in FIG. 3 there are four idler rollers 90, each mounted on a stub shaft 91 supported between parallel channel supports 92, 92; the outboard conveyor belts 70 and 73 having their respective stub shafts supported between one of the support members 92 and an extending outer or left-hand end portion of an adjacent side wall member 31 of the assembly 29 (see FIG. 3).

Adjuster means 95, 95 are provided on each of the support members 92 and the projecting end portions of sidewall members 31. Two such adjuster means are associated with each idler shaft 91 to slidably adjust such shaft and its roller 90 whereby to adjustably tension the conveyor belts 7073, according to known practice.

It is to be noted that the lower run of each conveyor belt, such as run 96 of belt 73 shown in FIG. 5, passes closely adjacent and operatively engages the bottom wall 33 of the plenum 30. This provides a seal for maintaining vacuum between the bottom wall of the vacuum plenum and sheet materials engaged with the belts. The upper belt runs (see run 97 of belt 73 in FIG. 5) pass freely over the plenums upper wall 38. It will be recognized from FIG. 5 that the upper run of the two interior belts 71 and 72 pass lengthwise along and within the two channel passageway means 50, 50, formed between the fixed and adjustable collar members 42, 43, 44 previously described. By this expedient the upper runs of the interior belts, which pass through the vacuum plenum and hood means, are completely isolated from the evacuated atmosphere therewithin.

It will be recalled from the earlier description of FIG. 1 that the operator of apparatus 10 has the capability of selectively rejecting and stacking sheet materials at the reject or prime stacking stations by controlling the reject controller 15. In order to accomplish this function, the preferred apparatus herein disclosed is provided with at least one selectively actuable valve means 100, as best shown in FIGS. 2, 3, 5 and 6 of the drawings.

As shown in FIGS. 5 and 6 in particular, valve means 100 comprises an elongated support bar 101 which extends transversely between the inner opposing faces of the two sidewall rail members 31, 31 of the plenum assembly, directly over the intermediate set of openings 35, 35. The support rail, as shown, may comprise an inverted C-channel member suitably fastened or otherwise affixed to and between the upright side wall members 31 as by bolt means 102 (see FIGS. 5 and 6). An elongated damper plate 103 comprising a rigid bar of generally inverted T-shaped cross section, shown best in FIG. 6, is supported immediately below the support bar 101 with a lower flange wall 104 thereof having three elongated and axially spaced pad portions 105 depending therefrom. The spaced relation of pad portions 105 conforms with the spacing between openings 35, 35 in the bottom wall 33 of the vacuum plenum. Cylindrical guide pins 106 pass through guide bushings 107 mounted on the support bar 101 and connect with the underlying damper bar 103 opposite the two outboard pads 105. Such pins guide the damper bar during vertical movement. Disposed generally centrally over the damper bar 103 and mounted atop the support bar 101 is an air piston and cylinder means 110 having a depending piston rod 111 which is pivotally fastened to the central web portion 112 of the damper bar by pivotal connector means 113.

In its normal inoperative position, damper bar 103 is raised as illustrated in FIG. 5. Upon suitable actuation of the piston and cylinder means 110, however, damper bar 103 moves downwardly to place the pads 105 registeringly over the underdisposed openings 35, thereby blocking off such openings. Actuation of the piston assembly 110 is pneumatically controlled by an electrical solenoid-actuated valve (not shown) in circuit with the controller and available to the operator at the inspection station. In the normal chain of events, valve means 100, as above described, remains in its raised or open conditions as shown in FIGS. 2 and 5 of the drawings. It is closed only upon appropriate actuation of the reject controller by the operator so as to selectively reject a panel or sheet of material as will appear hereinafter.

In order to guide sheet materials into the prime and reject stacks 13 and 14 as indicated in FIG. 2 of the drawings, apparatus 10 is equipped with appropriate guide means comprising two elongated guide rails 114 extending between legs 21, 21 on corresponding sides of the machine. Such rails are fastened to vertically adjustably crossbars 115 which crossconnect opposite legs 21 immediately beneath and adjacent to the lower runs of the conveyor belts and the vacuum plenum. Attached at right angles to the guide rails 114 are four metal guide bars 116 extending between the two side guide rails 114 on opposite sides of the machine. The guide bars are joined to guide rails 114 by adjustable slot and connector bolt means 117.

Each of the guide bars 116 has an outwardly flaired guide lip portion 118 along its upper margin while the side rails 114 are similarly provided with a guide lip portion 119 extending along the upper margin thereof (see FIG. 4). When assembled, the rails 114 and cross-connecting guide rods 116 provide a pair of rectangular funnel like guide chutes immediately adjacent the bottom side of the vacuum plenum and lower runs of the the several conveyor belts. This guide structure is adjustably positionable to define selected locations of the reject and prime stacks for the sheet materials. It will be understood that the vertical positioning and horizontal adjustment of the rails 114 and rods 116 is selected to accommodate the size and thickness of the sheet material to be handled by the machine. Thus, in accordance with the selected release of the sheet materials from the conveyor belts, as will be explained shortly, sheet materials are released and gravitationally discharged from the conveyor of apparatus 10 for guidance by the lip portions 113 and 119 into proper alignment with selected stack positions. In certain instances a boxlike stacker is used to receive the sheets as for example when handling fragile materials such as glass.

Having thus described the various assemblies and components of the illustrated apparatus 10 according to this invention, the use and operations thereof will now be set forth.

To operate the apparatus 10 hereinabove described, the blower and conveyor motors are electrically energized over appropriate starter controls. The speed of the conveyor belts is adjusted to effectuate a desired rate of advancement for the belts over the plenum between the feeder station and the reject or stacking stations 13 and 14. The blow motor speed is appropriately adjusted to effect a selected evacuation of the vacuum plenum 30, productive of a desired flow of air beneath the plenum and a desired difierential in ambient atmospheres or pressures between the interior of the plenum and the atmosphere at selected zones about the conveyor, particularly at the zones determined by the spacing and location of the openings 34, 35 and 36 in the bottom wall thereof. The partial vacuum within the vacuum plenum and the hood, is typically regulated within a normal range of 2 to 50 inches of water, dependent on the on one the sheet materials to be handled. The operation of the vacuum system employed in the present invention is based principally on high-volume, lowvacuum control in which air movement is an important factor as will appear presently. Belt speeds also are regulated within the range of 200 to 600 feet per minute, depending on the material being handled. Direction of movement of the belts beneath the vacuum plenum is according to a desired direction of movement for the sheet materials, as permitted by the reversible drive means for the belt conveyor.

In operating apparatus 10 in conjunction with an infeeding belt conveyor means 11, as set forth in FIG. 1 of the drawings, sheet materials are conveyed one-by-one along the upper run of the belt conveyor means 11 and brought substantially opposite the first line of openings 34, 34 in the bottom wall of the plenum. As each sheet approaches the openings 34, 34 the differential in ambient pressure as well as the velocity and movement of air through such openings 34 serves to draw each sheet and more particularly the leading edge thereof, upwardly from conveyor 11 to contact the underface of the adjacent runs of the several moving belt means 70-73. Frictional engagement between the sheet materials and the belts of the conveyor means, serves to rapidly drag or move the sheet materials in the direction of advancing movement of the belts along the underside of the vacuum plenum. Selected release and discharge of the sheets from the belts results in their even tual deposit at the prime and reject stacks or stations 13 and 14 respectively.

To better appreciate the novel aspects of the infeed operation and functioning of apparatus 10, reference is now had to FIGS. 8 through 11 of the drawings which show apparatus 10 in combination with a vertical stack feeder 121, as opposed to the continuous belt feeder 11 illustrated in FIGS. 1 and 2.

As shown best in FIG. 8 of the drawings, the stack feeder 121 is disposed immediately beneath the left-hand end of the plenum and conveyor assembly 29 so that the leading edge of the stack 122 of sheet materials is aligned generally in registration below or slightly past the rearward edge 123 of the several openings 34 in the bottom wall of the plenum chamber 30. As indicated by the air flow arrows in FIG. 8, a top sheet 1220 on the feeder 121 is subjected to an evacuated atmosphere on the upper face thereof, with the air moving rapidly across such upper face into openings 34. Importantly, a vertical air component races across leading edge 124 of the top sheet 122a almost directly toward openings 34. This component in conjunction with the evacuated atmosphere on the upper face of such top sheet serves to lift the leading edge 124 thereof preferentially upward, separating the same from stack 122 as illustrated in FIG. 9 of the drawings. This upward movement is assisted by the nonevacuated or generally normal atmospheric pressures on the underside or face of the top sheet, particularly effective when the leading edge of the top sheet commences its upward lift towards openings 34. As the top sheet 122a of the stack moves upwardly and engages the lower belt runs beneath the bottom wall of the vacuum plenum, it is frictionally dragged forwardly (to the right in FIG. 10) by and with the direction of belt movement, indicated by arrow A in that FIG. Simultaneously, the differential in ambient atmospheres on the opposite faces of the sheet serves to effectively lift and hold the sheet against the lower run of the conveyor belts.

The evacuated atmosphere of the plenum is distributed over the upper face of each sheet held on the belts by means of the spacings between the separated belts 70-73 and the lower wall of the plenum; a seal being effected between the outboard belts 70-73 and the bottom wall of the vacuum plenum.

It will be recognized (FIG. that as soon as a sheet 122a engages the lower belt runs and moves over openings 34, the latter are effectively closed or valved off causing substantially full atmospheric pressure to bear against the lower face of such sheet. This feature serves to isolate the stack 122 from the upflow of air and the vacuum in plenum 30 and substantially eliminates the possibility of feeding two sheets at one time to the conveyor belts. Thus an effective single sheet separating function is performed in the manner illustrated particularly in FIGS. 9 and 10 of the drawings.

As each sheet 122a advances across the lower wall of the plenum (see FIG. 11), its trailing edge eventually passes beyond openings 34 which permits air to rush directly through such openings to separate the next or succeeding sheet from the stack 122 repeating the separating and feeding functions above described. It further is to be noted that as the trailing edge or end of a sheet 122a is moved past the openings 34 to open the latter, the leading or forward margin of such sheet meanwhile moves over the next or succeeding set of openings 35, 35 by which the evacuated atmosphere across the upper wall of the sheet is reinforced to maintain the same tightly against the belts of the conveyor. It will be understood by those familiar with the art, that the stacker feeder 121 automatically feeds upwardly upon removal of each sheet to index the next succeeding or top sheet into a FIG. 8 position of proximity with openings 34 so that the up flow of air across the leading edge thereof and the evacuated atmosphere thereabove can effectively lift such sheet upwardly to repeat the separating and feeding functions.

It has been observed in operation that as each sheet leaves the upper end of the stack 122 and engages the conveyors, (see FIG. 9), it tends to fly or float forwardly in the direction of belt movement in response to the movement of air toward openings 34 and the upward atmospheric lift thereon. Such described upward feeding movement of each sheet, also occurs when using an infeed conveyor, such as conveyor 11 shown in FIG. 2.

Having fed a sheet to the apparatus 10, either from the belt conveyor means 11 or the stacker feeder means 121, as described, the sheet advances with the lower belt runs away from openings 34 toward openings 35; the spacing between such sets of openings importantly being slightly less than the length of the sheet being handled, so as to effectively maintain an evacuated atmosphere on the upper face of the sheet to hold the same in contact with the belts. As noted hereinabove, the vacuum effect is distributed over the upper face of the sheet by the open spacing between adjacent belts and the lower face of the vacuum plenum; such vacuum effect being most intense directly opposite the zones determined by the location of the several sets of spaced openings 34, 35 and 35 in the bottom of the vacuum plenum.

As each sheet advances past openings 35 and approaches openings 36, the latter serve to pick up the leading edge of the advancing sheet, reinforcing the vacuum effect to maintain the same on the lower side of the belt conveyor. However, as the leading edge of each sheet advances beyond openings 36, the vacuum effect on the upper face of said sheet, particularly adjacent the leading edge or margin 124 thereof gradually diminishes. By the time the leading edge of the sheet approaches guide lip 118 presented by the guide means over the right-hand margin of the prime stacking station 13, gravity effect or weight of the sheet in conjunction with the diminished vacuum effect on the upper face thereof causes the leading edge of the sheet to move downwardly sufficiently to engage such guide lip [18.

In certain cases, depending on the thickness and weight of the sheet materials being involved, it is desirable and fully contemplated, according to this invention, that a resilient stop barrier be provided adjacent the right-hand guide lip 118 shown in FIG. 2, to positively arrest forward movement of sheet materials therepast. In any event, as the sheets engage the guide lip,118 directly over the prime stack station 13, the effective gripping activity created by the evacuating atmosphere on the upper surface of the sheet is released sufficiently to permit the sheets to gravitate or drop downwardly through the guide means 118 which serve with guide means 119 to align the sheets over the prime stack station for deposit thereat.

In the event that the operator inspector notes a defective sheet 12 on the incoming conveyor means 11 in the illustrated set up of FIG. 1, he may bring about automatic deposit of such defective sheet at the reject station or stack 14, by pressing the reject controller button 15 which serves to automatically lower the valve over the intermediate set of openings 35, 35. With openings 35 closed, a similar deposit function in respect to the reject station or stack to that described above occurs. That is to say, with the vacuum effect eliminated about the zone adjacent openings 35, 35, the evacuated atmosphere on the upper face of the sheet selected for rejection is insufficient to maintain that sheet against the undersurface of the moving belt runs. Therefore, the leading edge of the sheet falls downwardly as the same advances past the valved off openings 35. The guide means over the reject station serve to receive the falling sheets and guide the same downwardly onto the reject stack at station 14.

It should be noted that by reversing the direction of the belt movement and using a vertical stack feeder, such as unit 121, of FIGS. 8 through 11, beneath the prime stack station for example, feeding and separating functions as illustrated in FIGS. 8-11 may be accomplished by openings 36, 36. Thus sheet materials may be fed from beneath the apparatus 10 to the left as viewed in FIG. 2 for deposit on the conveyor means 11 or other receiving devices. In the event that this latter arrangement is employed in conjunction with belt conveyor 11 illustrated in FIG. 2, it is of course necessary to reverse the latters direction of movement to carry off the sheets.

Further, whereas the illustrated apparatus 10 includes only one valve means 100, associated with the intermediate set of openings 35, 35, such a valve means may accompany each set of openings formed in the lower wall of the vacuum plenum so as to permit the selective closing off of any one or more sets of openings as required. It is to be recognized that it is not necessary to stack materials with apparatus 10 in the manner heretofore described. It is fully contemplated that apparatus of the type illustrated may be used in conjunction with one or more belt conveyors or other conveying means running therebeneath so that sheet materials fed into one end thereof, as by vertical stacker 121 or incoming belt conveyor 11 illustrated in the drawings, may be deposited on one or more conveyor means for distribution to remote locations From the foregoing it is believed that those familiar with the art will readily recognize and appreciate the novel concepts and combinations involved in the present invention which marks the same as an advancement in the material-handling art. Further, while the hereinabove-described embodiment of this apparatus sets forth certain details and aspects of a preferred form thereof, it is to be understood that the same is susceptible to numerous changes, modifications and substitutions of equivalents without departing from the spirit and scope of this invention.

lclaim:

1. In material-handling apparatus for handling generally planar sheet materials, the combination comprising: an elongated vacuum plenum, means for continuously evacuating the interior atmosphere of said plenum to subambient pressures, one elongated wall on said plenum having plural sets of spaced openings formed therethrough and located at axially spaced positions along the length thereof whereby the subambient pressures within said plenum are communicated to correspondingly spaced zones adjacent the exterior of said wall, each zone extending generally normal to the longitudinal axis of said wall with the spacing between adjacent sets of openings and associated zones being substantially equal to the length of the sheet materials being handled; imperforate conveyor means movable lengthwise over the exterior of said wall and along opposite end boundaries of said zones; means for driving said conveyor means continuously, and means for positioning individual sheets of material successively in predetermined spaced relation to said conveyor means at any one of said zones, as selected, such that a leading edge of each such positioned sheet is generally opposite the set of openings thereat, whereby the flow of air across said leading edge into said openings and the differential in ambient pressures on opposite surfaces of the related said positioned sheet cooperate to antigravitationally transfer the latter onto the exterior of said conveyor means for movement by and with the latter over said openings at said selected zone; said movement of the said sheet over said openings serving to effectively isolate the next positioned sheet from the subambient pressures of said selected zone while causing said subambient pressures thereof to generate throughout the space bounded by the adjacent surface of said sheet, said conveyor means and the opposing exterior surface of said wall to antigravitationally hold said sheet tightly against said conveyor means for movement with the latter; the said next positioned sheet remaining isolated from said subambient pressures of said selected zone so long as any portion of the previously transferred sheet substantially covers said set of openings thereat.

2. The combination of claim 1 wherein said conveyor means comprises at least two parallel spaced endless belts continuously orbital lengthwise about said plenum adjacent the opposite ends of said zones and adapted to effect an atmospheric seal between the exterior surface of said one wall and the adjacent opposing surface of sheet materials being held on said conveyor means thereby to effectively assist the generation of said subambient pressures through said space.

3. The combination of claim 1 and means for selectively regulating said evacuating means to effect selected levels of subambient pressure within said plenum whereby to regulate the antigravitational transfer forces according to the density and weight of the sheet materials being handled.

4. The combination of claim 1 wherein said conveyor means comprises a plurality of endless belts orbital along spaced paths paralleling the lengthwise axis of said one wall, and wherein each said set of openings comprises plural laterally spaced, generally elongated openings having coaxial lengthwise axes oriented substantially at right angles to said axis of said wall, and having a single run of said endless belts moveable between opposing ends of adjacent openings.

5. The combination of claim 1 wherein said plenum is generally horizontal, and said means for positioning said sheets operably elevates a vertical stack thereof to position successive uppermost sheets of said stack for transfer to said conveyor means.

6. Material-handling apparatus for transferring and stacking sheet materials of substantially uniform length comprising: a generally elongated hollow vacuum plenum mounted to extend horizontally over and between an infeed station and remote reject and prime stacking stations, means for continuously evacuating the interior atmosphere of said plenum to selected subambient pressures, imperforate conveyor means movable over the bottom wall of said plenum, adjacent the lateral limits thereof; means for continuously actuating said conveyor means including means for regulating the speed of movement thereof; said plenum having plural sets of openings formed through said bottom wall at axially spaced locations therealong and between said lateral limits thereof, the spacing between adjacent sets of openings being substantially equal to the len th of sheet materials being handled, each said set being a lgned along an axis generally normal to the lengthwise axis of said plenum and said openings thereof serving to communicate the subambient atmosphere within said plenum with the exterior of said bottom wall adjacent said sets of openings and said conveyor means; one set of said openings being located adjacently over said infeed station and at least one additional set thereof being located adjacently over each of said reject and prime stacking stations; means for positioning individual sheets of material one by one with a leading edge thereof in predetermined relation to said infeed station and proximate said conveyor means and said one set of openings thereat whereby the combination of air flow across said lead ing edge and a differential in ambient pressures on opposite surfaces thereof cooperate to antigravitationally lift each such positioned sheet onto said conveyor means for movement by and with the latter over said one set of openings at said infeed station; said movement of said sheet serving to effectively isolate the next positioned sheet from the subambient pressure and flow of air at said infeed station to prevent the same from being lifted onto said conveyor means until the sheet previously lifted thereon has cleared said one set of openings, each sheet so lifted onto said conveyor means being held thereon for movement therewith past successive sets of openings spaced along said plenum so long as said sheet substantially covers at least one of said sets of openings and being automatically released and gravitationally discharged from said conveyor means whenever the same fails to cover at least one set of said 7. The combination of claim 6 and valve means mounted within said plenum opposite the opposite the openings adjacent said reject station, and means remote to said reject station for selectively actuating said valve means to open and close said openings associated therewith, whereby sheets of material moved opposite said closed set of openings are selectively isolated from the subambient pressures within said plenum and are automatically released and gravitationally discharged to said reject station as soon as the same fail to cover the said set of openings at said infeed station.

8. The combination of claim 6 wherein the set of openings adjacent said prime stacking station is positioned to effect the automatic release and gravitational discharge of each sheet conveyed therepast to said prime stacking station, and guide means at said prime and reject stations for guiding sheets respectively discharged thereat into separate vertical stacks.

9. The combination of claim 8 wherein said conveyor means comprises a plurality of imperforate endless belts orbital about said plenum in spaced paths paralleling the longitudinal axis of said plenum, and each of said sets of openings comprises a plurality of laterally spaced elongated openings oriented with their lengthwise axes substantially at right angles to said belts and arranged with an endless belt run adjacent the opposite ends of each opening.

33g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,613,886 D d October 19, 1971 Invcntor(s) LOREN B. BARKER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE SPECIFICATION:

Col. 1, l. 22, insert "as" before aforesaid-; Col. 1, l. 40, "dependably" should read dependable-;

Col. 1, l. 74, "purpose" should read purposes:

Col. 2, l. 1, insert comma after "board";

Col. 2, l. 22, "a", second occurrence, should be deleted after "In";

Col. 3,l. 50, a period should be inserted after "drawings in place of the comma Col. 3, l. 73, "operative" should read --operatively--;

qol. 4, l. 15, "Roller" should read --Rollers:

Col. 4, l. 28, "variably" should read variable-;

Col. 4, l. 29, "adjustably" should be -adjustable Col. 4, l. 73 and continuing in C01. 5, l. l, "actuable" should be actuatable;

Col. 6, l. 19, "on one" should read -nature of-;

Col. 8, l. 49, after "It" insert -also-.

IN THE CLAIMS:

Col. 9, l. 63, last line of printing not clearly impressed should read -remote reject and prime stacking stations, means for continu- Col. 10, l. 38, insert "openings. as last word of claim;

Col. 10, l. 40, delete "opposite the", second occurrence.

Signed and sealed this 1 th day of April 1 972.

[SEALJ Lttest;

EDWARD M.FLETCHER,JR. ROBERT GOI'TSCHALK Lttesting Officer Commissioner of Patents 

1. In material-handling apparatus for handling generally planar sheet materials, the combination comprising: an elongated vacuum plenum, means for continuously evacuating the interior atmosphere of said plenum to subambient pressures, one elongated wall on said plenum having plural sets of spaced openings formed therethrough and located at axially spaced positions along the length thereof whereby the subambient pressures within said plenum are communicated to correspondingly spaced zones adjacent the exterior of said wall, each zone extending generally normal to the longitudinal axis of said wall with the spacing between adjacent sets of openings and associated zones being substantially equal to the length of the sheet materials being handled; imperforate conveyor means movable lengthwise over the exterior of said wall and along opposite end boundaries of said zones; means for driving said conveyor means continuously, and means for positioning individual sheets of material successively in predetermined spaced relation to said conveyor means at any one of said zones, as selected, such that a leading edge of each such positioned sheet is generally opposite the set of openings thereat, wherebY the flow of air across said leading edge into said openings and the differential in ambient pressures on opposite surfaces of the related said positioned sheet cooperate to antigravitationally transfer the latter onto the exterior of said conveyor means for movement by and with the latter over said openings at said selected zone; said movement of the said sheet over said openings serving to effectively isolate the next positioned sheet from the subambient pressures of said selected zone while causing said subambient pressures thereof to generate throughout the space bounded by the adjacent surface of said sheet, said conveyor means and the opposing exterior surface of said wall to antigravitationally hold said sheet tightly against said conveyor means for movement with the latter; the said next positioned sheet remaining isolated from said subambient pressures of said selected zone so long as any portion of the previously transferred sheet substantially covers said set of openings thereat.
 2. The combination of claim 1 wherein said conveyor means comprises at least two parallel spaced endless belts continuously orbital lengthwise about said plenum adjacent the opposite ends of said zones and adapted to effect an atmospheric seal between the exterior surface of said one wall and the adjacent opposing surface of sheet materials being held on said conveyor means thereby to effectively assist the generation of said subambient pressures through said space.
 3. The combination of claim 1 and means for selectively regulating said evacuating means to effect selected levels of subambient pressure within said plenum whereby to regulate the antigravitational transfer forces according to the density and weight of the sheet materials being handled.
 4. The combination of claim 1 wherein said conveyor means comprises a plurality of endless belts orbital along spaced paths paralleling the lengthwise axis of said one wall, and wherein each said set of openings comprises plural laterally spaced, generally elongated openings having coaxial lengthwise axes oriented substantially at right angles to said axis of said wall, and having a single run of said endless belts moveable between opposing ends of adjacent openings.
 5. The combination of claim 1 wherein said plenum is generally horizontal, and said means for positioning said sheets operably elevates a vertical stack thereof to position successive uppermost sheets of said stack for transfer to said conveyor means.
 6. Material-handling apparatus for transferring and stacking sheet materials of substantially uniform length comprising: a generally elongated hollow vacuum plenum mounted to extend horizontally over and between an infeed station and remote reject and prime stacking stations, means for continuously evacuating the interior atmosphere of said plenum to selected subambient pressures, imperforate conveyor means movable over the bottom wall of said plenum, adjacent the lateral limits thereof; means for continuously actuating said conveyor means including means for regulating the speed of movement thereof; said plenum having plural sets of openings formed through said bottom wall at axially spaced locations therealong and between said lateral limits thereof, the spacing between adjacent sets of openings being substantially equal to the length of sheet materials being handled, each said set being aligned along an axis generally normal to the lengthwise axis of said plenum and said openings thereof serving to communicate the subambient atmosphere within said plenum with the exterior of said bottom wall adjacent said sets of openings and said conveyor means; one set of said openings being located adjacently over said infeed station and at least one additional set thereof being located adjacently over each of said reject and prime stacking stations; means for positioning individual sheets of material one by one with a leading edge thereof in predetermined relation to said infeed station and proximate said conveyor means and said one sEt of openings thereat whereby the combination of air flow across said leading edge and a differential in ambient pressures on opposite surfaces thereof cooperate to antigravitationally lift each such positioned sheet onto said conveyor means for movement by and with the latter over said one set of openings at said infeed station; said movement of said sheet serving to effectively isolate the next positioned sheet from the subambient pressure and flow of air at said infeed station to prevent the same from being lifted onto said conveyor means until the sheet previously lifted thereon has cleared said one set of openings, each sheet so lifted onto said conveyor means being held thereon for movement therewith past successive sets of openings spaced along said plenum so long as said sheet substantially covers at least one of said sets of openings and being automatically released and gravitationally discharged from said conveyor means whenever the same fails to cover at least one set of said
 7. The combination of claim 6 and valve means mounted within said plenum opposite the opposite the openings adjacent said reject station, and means remote to said reject station for selectively actuating said valve means to open and close said openings associated therewith, whereby sheets of material moved opposite said closed set of openings are selectively isolated from the subambient pressures within said plenum and are automatically released and gravitationally discharged to said reject station as soon as the same fail to cover the said set of openings at said infeed station.
 8. The combination of claim 6 wherein the set of openings adjacent said prime stacking station is positioned to effect the automatic release and gravitational discharge of each sheet conveyed therepast to said prime stacking station, and guide means at said prime and reject stations for guiding sheets respectively discharged thereat into separate vertical stacks.
 9. The combination of claim 8 wherein said conveyor means comprises a plurality of imperforate endless belts orbital about said plenum in spaced paths paralleling the longitudinal axis of said plenum, and each of said sets of openings comprises a plurality of laterally spaced elongated openings oriented with their lengthwise axes substantially at right angles to said belts and arranged with an endless belt run adjacent the opposite ends of each opening. 